Keeping E. coli, Parasites Out of Drinking Water

Last summer, about 1,000 county fair goers in upstate New York had symptoms that were either suspected or confirmed as being caused by infection with Escherichia coli 0157:H7 bacteria. The likely source was drinking well water contaminated by animal manure in rain runoff.

Earlier incidents such as this had prompted the U.S. Department of Agriculture to begin a food safety and water quality project in 1996. The project was recently expanded to include several of USDA's Agricultural Research Service laboratories.

As a result, microbiologist Daniel R. Shelton will track the movement of E. coli and the parasite Cryptosporidium parvum in "rainwater" flowing down the sides of artificial hills called soil lysimeters. Shelton is with the ARS Environmental Chemistry Laboratory in Beltsville, Md.

The "rain" is actually water sprayed from a unique ARS-designed flexible boom that hugs the slope, ensuring that water droplets all fall an equal distance. The 15-foot-high soil lysimeters are about 40 feet wide by 70 feet long and lined with plastic.

This year, Shelton studied soil water movement. Next, he'll add C. parvum eggs to applied manure. Instead of E. coli 0157:H7, he'll trace benign E. coli strains. He will also test how well grass strips filter out pathogens.

This study is a prelude to larger scale studies that will be done in Beltsville and on a Pennsylvania dairy farm.

An article about the research appears in the November issue of ARS' Agricultural Research magazine, and on the web at:

/is/AR/archive/nov99/track1199.htm

Scientific contact: Daniel R. Shelton, ARS Environmental Chemistry Laboratory, Beltsville, Md., phone (301) 504-6582, fax (301) 504-7976, dshelton@asrr.arsusda.gov.